Washington Real Estate Investment Trust’s choice to retain Cassidy Turley to market its 3.1 million-square-foot Washington area portfolio was both a great opportunity and a significant challenge for the brokerage.

The publicly traded real estate investment trust had amassed a sizable collection of properties, amounting to 56 industrial buildings across Maryland and Virginia, and showing them all to prospective buyers was just “not feasible” the firm said. So the challenge became how to market the disparate properties. Cassidy Turley decided to break the holdings into four regions and developed an extensive campaign including printed materials and an interactive website allowing visitors to take a self-guided tour of the properties.

The brokerage distributed 150 offering memos to interested investors and received nine offers before picking AREA Property Partners as the portfolio’s new owner in a deal that took four separate transactions to complete.

3 Bethesda Metro Center

Location: 3 Bethesda Metro Center, Bethesda

Deal size: 368,400 square feet

Deal value: $150.1 million

Seller: The Meridian Group

Buyer: Brookfield Office Properties Inc.

Seller representative: Holliday Fenoglio Fowler LP

The Meridian Group’s sale of 3 Bethesda Metro Center marked one of 2011’s largest investment sales in suburban Maryland, at a sale price of more than

$150 million, or about $407 per square foot.

Holliday Fenoglio Fowler LP, which was retained to market the property, highlighted 3 Bethesda’s proximity to the Bethesda Metro station, its 93 percent occupancy rate and the site’s future development potential of up to 283,000 square feet among its features.

The 17-story building at Old Georgetown Road and Wisconsin Avenue was sold under a land lease that extends until Dec. 31, 2052, with options to extend the deal until the end of 2101.